Proper evaluation of drilling fluid (mud) friction coefficient (CF) depends on more than good test equipment. Detailed planning, statistical test design, and proper experimental technique are crucial to advanced technology for laboratory measurements of mud CF. Numerous factors affect these measurements. Technology which can rapidly screen selected factors, anticipates natural variation in measurements, effectively minimizes bias, and insures that responses tu test parameters are precisely measured is described. Moreover, a method for statistical data analysis which clearly and concisely summarizes the important features of experimental data is presented.

Specialized test equipment for accurately measuring mud CF between simulated tool joints and wellbore materials is described. Effects of tool joint type and surface condition, wellbore sample, and operating conditions are included. Twenty-eight mud lubricants were evaluated in two mud types weighing 9–16 Ibm/gal (1078–1917 kg/m3) using this advanced technology. Results of these tests are summarized.

Keywords:
drilling fluid property, mud lubricity tester, drilling fluid chemistry, base mud, drilling fluids and materials, drilling fluid formulation, mud cf, spe 19537, friction coefficient, laboratory measurement
Subjects:
Drillstring Design, Drilling Fluids and Materials, Drilling fluid selection and formulation (chemistry, properties)
Copyright 1989, Society of Petroleum Engineers
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